DEAR DOCTOR K: Iím an avid biker. But could my biking lead to erectile dysfunction?

DEAR READER: Biking is an excellent form of exercise. But occasionally, if men who bicycle many hours each week are not careful, it can lead to temporary erectile dysfunction. Your question caused me to review articles on this topic that have been published in medical journals.

It appears that there are no studies large enough to give us a good idea of just how often bicyclists develop this condition. The risk appears to be highest for men who cycle more than three hours a week. I canít find any published research study to support my speculation, but Iíll bet the risk is lower in using stationary bikes than in riding outdoors: The bumps in the road get transmitted through the bike seat.

One recent study compared 142 men in a bicycle club to 83 men who did not ride bicycles and found no difference in the rate of erectile dysfunction. This does not mean that frequent riding cannot cause sexual problems, but it probably means that it doesnít happen very often.

The reason avid bikers sometimes get erectile dysfunction is that the seat puts pressure on the perineum. Thatís the area between the genitals and anus that contains the nerves and arteries that run into the penis. A narrow bicycle seat places pressure on the perineum, compressing crucial nerves and arteries. This pressure can harm nerves and temporarily hinder blood flow, causing tingling or numbness in the penis and, eventually, ED.

Taking a few simple precautions when biking can help prevent sexual dysfunction:

If you feel tingling or numbness in your penis, stop riding for a week or two. These are warning signs that your biking could lead to erectile problems. Even if you donít feel any warning symptoms, itís a good idea to change your position and take breaks during long rides.

Perhaps the best advice is to make biking one part of a balanced fitness program. Alternate riding with walking, jogging or swimming. Climb off your stationary bike and get on a treadmill, elliptical trainer or stair climber.